I have created a Customer and that customers has 3 contact person names. Now while creating the Sales Order, I want to select 1 contact person name from a list. How can I get only the names of the contact person into a field?

I have created a related field in my custom module and in the form view I have displayed it :

custom.py

customer_contact = fields.Char(related="partner_id.child_ids.name", string="Contact Person", )

custom_saleorder_views.xml

<xpath expr="//field[@name='partner_shipping_id']" position="after">
    <!-- Add your fields or attributes here -->
    <field name="customer_contact" />
</xpath>

I have displayed the field below the Delivery address.

Now when I select the customer in Sales Order form view, it gives only the first contact person name. The rest of the contact names are not displayed.

How to get a list of contact names in the field "customer_contact". As the default field type of 'name' field is 'Char', using many2one field in our custom module gives a error.